"Kyrie is one of the best scorers in the NBA," Ainge said in the Celtics' news release to announce the blockbuster trade in which the Cavs sent Irving to Boston for Isaiah Thomas, Jae Crowder, Ante Zizic and Brooklyn's No. 1 pick.

"He has proven that on the biggest stage, the NBA Finals, the last three years," Ainge said. "He's been an NBA champion, an Olympic gold medalist, and a four-time All-Star. For all he's accomplished, we think his best years are ahead of him."

Thomas has been Boston's best player the last two seasons -- in which he was an All-Star, an All-NBA selection and the league's No. 3 scorer last season -- and endeared himself to the organization and community by playing hurt and through the death of his sister during the playoffs.

Crowder spent the last three seasons with the Celtics.

"Isaiah embodied what it meant to be a Celtic," Ainge said. "He captured fans' hearts not only with his spirit, but his personality. Jae's toughness was contagious for our team. He improved his skills each year, but it's his energy and fight that will be remembered. We wish them and their families the very best."

Celtics co-owner Wyc Grousbeck said of Thomas and Crowder: "Isaiah and Jae have been a huge part of our success. Isaiah's playoff performance under very difficult circumstances will live on in history, and we wish them all the best."